Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 24, 2025
On these determinations Guibourt founded a theory of the mode of formation of tabasheer based on the suggestion that at certain periods of its growth the bamboo needed less silica than at other times, and that when not needed, the silica was carried inward and deposited in the interior. The specimens examined were obtained from the Bambusa apus, growing in the Residency of Bantam.
Continually washed by the spray of the cascade, this gold appeared in all its brilliance, as if ready to escape from the silica which held it, and thus perhaps for centuries this king's ransom had hung menacingly over the abyss!
The latter idea has been already disposed of, but if not, it may be dismissed with the statement that the heat which would melt silica in the masses met with in lodes would sublimate any gold contained, and dissipate it, not in nuggets but in fumes.
Platinum has, however, become so valuable that it is liable to theft unless constantly under the protection of the user. As constant protection is often difficult in instructional laboratories, it is advisable, in order to avoid serious monetary losses, to use porcelain or silica crucibles whenever these will give satisfactory service.
Possibly, but of this I have no evidence, mercury was used to retain the gold on the riffles, as previously stated. This method of saving the precious metal was known to the ancients. At a mine of which I was managing director the lode was almost entirely composed of sulphide of iron, carbonate of lime or calcspar, with a little silica.
The term was subsequently made to include other rocks, such as clinkstone and obsidian, which have the same mineral composition, but to which, owing to their different texture, the word in its original meaning would not apply. The feldspars which occur in Trachytic rocks are invariably those which contain the largest proportion of silica, or from 60 to 70 per cent of that mineral.
The inhabitants, Bushmen and Bakalahari, prey on the game and on the countless rodentia and small species of the feline race which subsist on these. In general, the soil is light-colored soft sand, nearly pure silica. The beds of the ancient rivers contain much alluvial soil; and as that is baked hard by the burning sun, rain-water stands in pools in some of them for several months in the year.
These fusaioles are generally of common clay mixed with bits of mica, quartz, or silica, though some few have been found at Mykenae and Tiryns of steatite. The clay whorls before being baked were plunged into a bath of a very fine clay of gray, yellow, or black color, and then carefully polished.
It might therefore have been supposed that the analyst was here altogether at fault, and that at any rate its artificial production must be impossible. Nevertheless, this has been accomplished, and simply by combining in the proper proportions, as determined by analysis, silica, alumina, soda, iron, and sulphur.
Seeing that, in most cases, they would be hermetically enclosed in molten and quickly solidifying silica they could not be acted on to any great extent by aqueous agency. Neither does Mr.
Word Of The Day
Others Looking